Jacot lathe help

[Knebo]

Hello everyone, 

Today, I finally wanted to try out my Jacot lathe by Steiner. I bought it months ago but just admired it. 

Unfortunately, by just playing around with it and turning all the knobs, I moved one thing and can't move it back. I don't know any of the terminology, so I hope the picture will make it clear. 

When I screw inwards the part 1 all the way, it will start moving part 2 towards the left. 

BUT I don't know how to move it back to the right!! Help! 

Screwing part 1 outwards -as I had on the picture- just removes it. 

 

 

[nickelsilver]

The shaft that positions the pulley is keyed, and the key is the screw you see there on the side. Often folks who want to take the tool apart will try to unscrew that screw, but it will only come out once the shaft is out. If you turn it with force it raises burrs on the shaft, making it stick in the bore.

 

The whole assembly comes out the left side, the boss on the tool is threaded in. If you remove the upright pin for the pulley (held by a set screw, and generally rather tight in its bore), you can unscrew the boss, and pull the whole works out the left side. It should unscrew without too much force, protect it with carton or something if you grip it with pliers (I grab it in a 10mm lathe collet but I have a large lathe). Check the shaft for burrs along the keyway, pull the screw on the side and check the flats for burrs. You can remove any with a fine file.

Edited October 23, 2024 by nickelsilver

[Knebo]

1 hour ago, nickelsilver said:

The shaft that positions the pulley is keyed, and the key is the screw you see there on the side. Often folks who want to take the tool apart will try to unscrew that screw, but it will only come out once the shaft is out. If you turn it with force it raises burrs on the shaft, making it stick in the bore.

 

The whole assembly comes out the left side, the boss on the tool is threaded in. If you remove the upright pin for the pulley (held by a set screw, and generally rather tight in its bore), you can unscrew the boss, and pull the whole works out the left side. It should unscrew without too much force, protect it with carton or something if you grip it with pliers (I grab it in a 10mm lathe collet but I have a large lathe). Check the shaft for burrs along the keyway, pull the screw on the side and check the flats for burrs. You can remove any with a fine file.

Wow, thanks so much!! 

Well, I've taken it apart as far as I could now. 

Now I'm supposed to unscrew this bit highlighted with the blue arrow, right? With pliers. 

[nickelsilver]

Yes, unscrew that, then you can pull the whole assembly out that side. It's a normal thread (unlike the thread that moves the pulley position shaft). If the keyed shaft does have burrs, it might take some effort to pull it all out, that's normal.

[Knebo]

@nickelsilver, honestly, I can't thank you enough!!

Without you, I'd NEVER have figured this out. And would probably have caused damage to the tool in the process. 

I followed your guidance (everything was VERY hard to remove) and found massive burrs (more like proper deformation/bending) in the shaft around the screw on the side. See below the picture of the screw (this was not me!). You can deduct from there how bad it was...

Anyway, I filed away the burrs/deformation and now it's working very nicely! I'm super happy!

Edited October 23, 2024 by Knebo

[nickelsilver]

That's great! I have had at least a dozen of these (at least) over the years, and seen 2 or 3 where that screw/key had half the head cracked off, and of course the shaft was well stuck.

 

Another common issue is the runner the pulley rides on gets knocked out of true. That's hard to rectify if you don't have a lathe you can put it in (it's 5mm diameter). In the lathe, you can put an indicator on it and bump it back true.

 

A very nice feature on these Steiners is that you can adjust the headstock to line up perfectly to the tailstock. I seem to remember explaining the procedure once, will try to find the post.

[Knebo]

5 minutes ago, nickelsilver said:

A very nice feature on these Steiners is that you can adjust the headstock to line up perfectly to the tailstock. I seem to remember explaining the procedure once, will try to find the post.

that would also be great!

[Knebo]

I've burnished my first pivot this evening!

It was a nice learning process. @VWatchie's youtube video was very helpful in getting a good hand position and feel - thanks! It took me some time to get a smooth and fast-enough motion, but I kinda got there (to "ok", not yet great) after some time. The pivot I was practicing on came out nice and shiny after a few tries.

I'm super happy for today ! Will practice some more soon. 

Edited October 23, 2024 by Knebo

[Knebo]

22 hours ago, nickelsilver said:

That's great! I have had at least a dozen of these (at least) over the years, and seen 2 or 3 where that screw/key had half the head cracked off, and of course the shaft was well stuck.

 

Another common issue is the runner the pulley rides on gets knocked out of true. That's hard to rectify if you don't have a lathe you can put it in (it's 5mm diameter). In the lathe, you can put an indicator on it and bump it back true.

 

A very nice feature on these Steiners is that you can adjust the headstock to line up perfectly to the tailstock. I seem to remember explaining the procedure once, will try to find the post.

I found your post on adjusting the headstock. Here it is:

 

[nickelsilver]

Ah cool- I was sure I had written on it, but not sure when (feels like longer ago!).